Derek J. Gable U.S. Pat. No. 4,325,240 disclosed a locking mechanism particularly useful in keysafes and similar devices wherein two correct and related inputs are necessary for opening of the mechanism. Preferably, the two inputs are a programmer and a combination lock with a plurality of combination wheels. The structure is arranged so that, when a programmer is inserted, the internal lock mechanism is set in a unique position so that a unique setting of the combination wheels is necessary for opening the lock.
When the keysafe has been opened and subsequently closed, it is preferable to reset the combination wheels to a reference position. Quite often, this reference position is an all ones position. It is, thus, desirable to have a mechanism for requiring that each combination wheel be reset to one.